• Proceedings of the Korea Water Resources Association Conference
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• 한국수자원학회 2016년도 학술발표회
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• pp.469-469
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• 2016

본 연구에서는 지진해일 모의결과를 바탕으로 하여 지진해일모형 결과에 민감하게 작용할 수 있는 다양한 입력조건을 분석하였다. 우선 2004년 인도양 지진해일 모의를 위하여 다중격자체계를 갖추고 있는 COMCOT모형과 수심적분된 Boussinesq모형의 결합모형을 사용하였으며, 근해역에 지진해일 충격 및 피해산정 결과에 유효한 영향을 주는 입력인자를 파악하기 위하여 4가지의 시나리오를 설정하였다. 각 시나리오에서는 3개의 서로 다른 독립인자가 포함되었으며 이들은 배타적으로 결정되어 최소한의 시나리오로 다양한 분석이 가능하도록 하였다. 즉, 시나리오 1에서는 지진해일의 초기수면상태를 산정하기 위한 간략화된 단층모형을 적용하였고, 이 때 바닥마찰에 대한 고려는 배제되었다. 시나리오 2에서는 시나리오 1과 모든 조건은 동일하게 하였으나 유한단층 모형을 통해 초기수면상태를 산정하도록 하였다. 이처럼 유사하게 시나리오 3에서는 복잡한 지형 특성을 나타내는 몰디브 지역의 보다 정확한 해석을 위하여 몰디브 지역의 상세격자망을 추가적으로 다중격자체계에 포함시켰다. 마지막으로 바닥마찰항에 대한 민감도를 분석하기 위하여 시나리오 4에서는 바닥마찰항에 대한 고려를 포함시켰다. 또한, 4가지 시나리오 외에 결합모형의 성능을 평가하기 위하여, COMCOT모형만을 사용하는 시나리오를 추가적으로 설정하였다. 즉, 시나리오 1과 모든 조건은 동일하되 COMCOT모형만을 사용하도록 하였다. 설정된 조건에 따른 수치모의 결과, 지진해일 내습에 따른 해수위 변화는 각 시나리오별로 큰 차이를 보이지 않았으나, Boussinesq모형에 의한 지진해일의 동수역학적 거동은 COMCOT모형을 사용한 결과와 유의한 차이를 보였으며, 특히 파랑에 기인한 난류적 거동은 극명한 대조를 이루었다. 따라서, 본 연구결과를 통해 향후 파랑에 기인한 난류적 거동의 정확모의를 위해 수치해석에 따른 확산오차 및 바닥마찰항에 대한 면밀한 연구가 필요함을 시사하였다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• 제28권6호
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• pp.232-241
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• 2016

Installing a ventilator for an apartment house composed of over 100 dwelling units was mandated in 2006 to improve indoor air quality. In the case of mechanical ventilators, the air change rate is kept stable, however 68% of dwellers do not operate their ventilator because of an increased electrical bill and noise. In the case of natural ventilators, the former problems are settled, but there are concerns about cold draught and an increase of heating/cooling cost. Authors are developing a heat recovery type natural ventilator which is a natural ventilator equipped with total heat recovery element, and it is expected that those problems of mechanical ventilator and natural ventilator are resolved by this. The combined type diffuser of this study is an under developed fit to the heat recovery type natural ventilator above. There are no standards to evaluate the performance for this type of diffuser. Due to this issue this study investigated the performance of the ventilation and maintained a thermal environment for the combined type diffuser by comparing it with existing diffusers. The results revealed that the performances of the combined type of diffusers showed different features from the existing ones, and was estimated to be high enough in the performances above.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• 제16권12호
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• pp.1204-1211
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• 2004

It is difficult to apply a conventional selection guide for diffusers when the diffuser is installed in a perimeter zone, because the air diffusion performance index (ADPI) vs. throw/length (T/L) ratio curve listed in conventional guide does not consider the perimetric heating load through the walls. The objective of this study is to evaluate the effect of the perimetric heating load on the ADPI and propose a selection guide for a proper line diffuser when perimetric heating load exists. The velocity and temperature distributions and the ADPI values are obtained numerically with various heat load ratios and air flow rates. The velocity and temperature distributions and the ADPI values are analyzed by CFD in case of various heat load ratios and air flow rates. Also, ADPI was calculated by those results. The ADPI values by numerical results are compared with an existing experimental data to verify the method for the evaluation of ADPI proposed in a present study. In case of a line diffuser installed at the high side wall, the ADPI decreases according to the increases of the flow rate on every heat load ratio of the present study except 0.75. The ADPI vs. T/L ratio curves have been proposed for the heat load ratios of 0.25, 0.5, 0.75 to guarantee the comport thermal environment when diffusers are installed in perimeter zone.

• Journal of the Korea Society of Computer and Information
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• 제26권12호
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• pp.299-307
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• 2021

As the COVID-19 pandemic spread around the world, more and more universities are conducting real-time distance video lectures using ZOOM, Webex, and MS Teams. This study attempts to identify the factors influencing learner satisfaction of real-time distance video lectures. Based on the existing research, it was composed of five elements (system factor, content quality, interaction, self-direction, and learning motivation) as learner satisfaction elements of real-time distance video lectures. As a result of analyzing the structural equation model of 160 effective questionnaires by conducting a survey of college students in the metropolitan and Chungcheong areas, it was found that three factors (interaction, self-direction, and learning motivation) influence learner satisfaction. Real-time distance video lectures are expected to continue to expand in the future. Therefore, universities should continuously increase learner satisfaction through the development and evaluation of real-time distance video lecture satisfaction models.

• Journal of Digital Convergence
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• 제17권2호
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• pp.113-125
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• 2019

Mobile social commerce is one of the fastest growing distribution channels in recent years. Therefore, it is important to understand customer's buying behavior in mobile social commerce in order to continuously grow in the competitive mobile social commerce market. To achieve the purpose of this study is to investigate how impulsive buying behaviors are applied in mobile shopping and how factors affect impulse purchasing in online shopping. In order to verify the hypothesis, we surveyed the customers who have experiences of using mobile social commerce and analyzed 280 valid data by Smart PLS 3.0. As a result, it was confirmed that consumers' innovation and purchasing experience influenced impulse purchase in mobile social commerce, and scarcity messages among information attributes affect impulse buying. Through this study, impulsive buying behavior which is a frequently analyzed variable in an online shopping context will be extended to the mobile shopping context. and it will provide practical implications for customer strategy establishment in mobile social commerce market.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• 제14권3호
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• pp.1-11
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• 2019

Based on the knowledge spillover theory of entrepreneurship(KSTE) and resource based view(RBV), this study examines that how patent based entrepreneurship impacts on improving key performances such as financing, firm innovation, sales, product selling growth, employment. This study which is conducted with data from 353 startup firms indicates that patent based entrepreneurship has positive effects on performance of financing, innovation, product selling growth, and employment. On the other hand, there is no effect of patent-based entrepreneurship on sales performance. This statistical results were the same The results were the same when the independent variables were measured as intensity of patent based entrepreneurship which indicates the rate of patent based product or service among total number of product or service of the startup company.

• Convergence Security Journal
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• 제21권1호
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• pp.79-92
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• 2021

In a society where ICT technology is converged, the use of various network-connected devices such as IoT is spreading. Network-connected devices are inevitably exposed to the threat of hacking such as information leakage, and countermeasures need to be prepared to respond. Security certification system for IoT devices has been introduced to promote security of IoT products, and for this purpose, legalization and standardization of certification standards and methods are in progress. In line with this, in Korea, as the Information and Communication Network Act was revised in 2020, ICT convergence devices connected to the network were newly defined as "information and communication network connected devices," and the basis for the security certification system is being established. We summarized related domestic and foreign trends and suggest specific considerations for implementing the security certification system for IoT devices in South Korea.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• 제9권1호
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• pp.179-187
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• 2019

With the recent development of small computing devices, IoT sensor network can be widely deployed and is now readily available with sensing, calculation and communi-cation functions at low cost. Sensor data management is a major component of the Internet of Things environment. The huge volume of data produced and transmitted from sensing devices can provide a lot of useful information but is often considered the next big data for businesses. New column-wise compression technology is mounted to the large data server because of its superior space efficiency. Since sensor nodes have narrow bandwidth and fault-prone wireless channels, sensor-based storage systems are subject to incomplete data services. In this study, we will bring forth a short overview through providing an analysis on IoT sensor networks, and will propose a new storage management scheme for IoT data. Our management scheme is based on RAID storage model using column-wise segmentation and compression to improve space efficiency without sacrificing I/O performance. We conclude that proposed storage control scheme outperforms the previous RAID control by computer performance simulation.

• Journal of the Korea Convergence Society
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• 제12권1호
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• pp.37-47
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• 2021

In the pandemic era, smart medical technology has also been applied to prevent and control diseases such as COVID-19. Health QR code system shave sparked recent discussion in the hopes of improving its convenience and safety. The many types of current health QR code systems in China exists causes inconvenience to those that are vulnerable, as well as raising the issue of personal information protection. In order to solve this problem, this paper proposes transparent integration of the health QR code systems and the process of protecting personal information, as well as designs an interface for user convenience. Through the method presented in this paper and the newly designed interface, users can enjoy the smart pharmaceutical system more conveniently and safely, and ensure effective results in the prevention and control of diseases that are likely to spread.

• Journal of Korea Society of Industrial Information Systems
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• 제26권4호
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• pp.59-71
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• 2021

This study investigates the effects of restaurants' physical environments on customers' words of moth and return intention. Data was collected using a self-administered questionnaire from restaurants during summer of 2020 and received 627 useful responses. The data was analyzed using the hierarchical multiple regression. The results showed that restaurants' physical environments was statistically significant influencing factors on customers' positive word-of-mouth and return intention. Hygiene environmental variables did not moderated the relationship between restaurants' physical environments and customers' word-of-mouth whereas hygiene environmental variables did moderated the relationship between restaurants' physical environments and customers' return intention. The results of this study suggested that restaurant business owners need to maintain clean environment and to continuously educate employees to protect customers from COVID-19 spread.